Enhanced scale inhibitor squeeze treatment using a chemical additive

ABSTRACT

Compositions and methods for the use in scale inhibitor squeeze treatments are provided. In some embodiments the present disclosure provides a method including introducing a pre-flush fluid into at least a portion of a subterranean formation, the pre-flush fluid including a choline chloride chemical additive; and introducing a treatment fluid including a scale inhibitor into the portion of the subterranean formation after at least a portion of the pre-flush fluid has been introduced into the portion of the subterranean formation.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 17/498,299 filed Oct. 11, 2021, published as U.S.Patent Application Publication No. 2022/0120159 A1, and entitled“Enhanced Scale Inhibitor Squeeze Treatment Using a Chemical Additive,”which claims priority to U.S. Provisional Application No. 63/092,657,filed Oct. 16, 2020, both of which are incorporated herein by referencein their entirety.

BACKGROUND

The present disclosure relates to methods, compositions, and systems fortreating subterranean formations to reduce the formation of scalestherein.

Oilfield fluids (e.g., oil, gas, and water) may be complex mixtures ofaliphatic hydrocarbons, aromatics, hetero-atomic molecules, anionic andcationic salts, acids, sands, silts, clays and a vast array of othercomponents. The nature of these fluids combined with sometimes severeconditions of heat, pressure, and turbulence to which they are oftensubjected during retrieval, may be contributory factors to scaleformation in oil and/or gas production wells and surface equipment.Wherever water production occurs, the potential for some type of scaleformation may exist. “Scale,” as the term is used herein, may refer toany mineral or solid salt deposit that forms in a formation, forexample, when the saturation of formation water to one or more mineralsis affected by changing physical conditions (such as temperature,pressure, or composition), thus causing minerals and salts previously insolution to precipitate into solids. Scale deposits may include avariety of materials, including but not limited to calcium carbonate,calcium sulfate, barium sulfate, strontium sulfate, iron sulfides, andthe like. Scale deposits can form on any surface in a down holeoperation, including subterranean formations, production tubing, gravelpacking screens, and other well bore equipment. Scale can develop almostimmediately or build up over several months before becoming noticeable.The effect scale has on productivity may depend, at least in part, onthe type, location, and the mass deposited. Scale formation can becomeso severe as to restrict or even completely choke production. Theformation of scale can decrease permeability of the subterraneanformation, reduce well productivity and shorten the lifetime ofproduction equipment. In order to clean scale from wells and equipmentit may be necessary to stop production, which is both time-consuming andcostly.

The formation of scale may be controlled by the use of chemical scaleinhibitors that reduce or prevent the precipitation and/or deposit ofthese scales in the formation. Several methods are known in the art forintroducing scale inhibitors into production wells. For example, a solidform of a scale inhibitor may be placed into the formation; however,this method may be limited due to the fact that there are relatively feweffective solid scale inhibitors and each has functional or designlimitations. Another known method of placing scale inhibitor is a“squeeze” application in which a scale inhibitor is introduced into aformation and adsorbed or precipitates onto the reservoir rock surfacesand helps prevent or diminish scale deposition. However, it may bedifficult to confirm whether the scale inhibitor has been adsorbed ontothe rock surface with sufficient mechanical strength to avoiddisplacement by fluids flowing through the formation, and in an adequateamount to provide effective scale inhibition. In some cases, it mayrequire long periods of shut-in time to allow the scale inhibitor toadequately adsorb onto rock surfaces downhole.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments ofthe present disclosure and should not be used to limit or define theclaims.

FIGS. 1A and 1B are diagrams illustrating a scale inhibitor squeezetreatment according to certain embodiments of the present disclosure.

FIG. 2 is a graph illustrating data from desorption tests of certainmethods of the present disclosure.

FIG. 3 is a graph illustrating data from desorption tests of certainmethods of the present disclosure.

While embodiments of this disclosure have been depicted, suchembodiments do not imply a limitation on the disclosure, and no suchlimitation should be inferred. The subject matter disclosed is capableof considerable modification, alteration, and equivalents in form andfunction, as will occur to those skilled in the pertinent art and havingthe benefit of this disclosure. The depicted and described embodimentsof this disclosure are examples only, and not exhaustive of the scope ofthe disclosure.

DESCRIPTION OF CERTAIN EMBODIMENTS

Illustrative embodiments of the present disclosure are described indetail herein. In the interest of clarity, not all features of an actualimplementation may be described in this specification. It will of coursebe appreciated that in the development of any such actual embodiment,numerous implementation-specific decisions may be made to achieve thespecific implementation goals, which may vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthe present disclosure.

To facilitate a better understanding of the present disclosure, thefollowing examples of certain embodiments are given. In no way shouldthe following examples be read to limit, or define, the scope of theinvention. Embodiments of the present disclosure involving wellbores maybe applicable to horizontal, vertical, deviated, or otherwise nonlinearwellbores in any type of subterranean formation. Embodiments may beapplicable to injection wells, monitoring wells, and production wells,including hydrocarbon or geothermal wells.

The present disclosure provides methods, compositions, and systems forapplying and/or enhancing scale inhibitor squeeze treatments insubterranean formations by treating a portion of the formation with apre-flush fluid that includes one or more of chemical additives. Forexample, the methods and compositions of the present disclosure mayinclude a chemical additive that may, inter alia, target enhancement oftreatment life with a limited injected fluid volume. In certainembodiments, the chemical additives of the present disclosure may besubstantially or fully compatible with high salinity brine and thermallystable at reservoir temperature. In the methods of the presentdisclosure, a pre-flush fluid including one or more of these chemicaladditives may be introduced into at least a portion of a subterraneanformation, after which a treatment fluid including a scale inhibitor isalso introduced into that portion of a subterranean formation. Incertain embodiments, the fluids are introduced (e.g., injected orpumped) into the formation via a well bore penetrating the subterraneanformation, and are introduced at a pressure sufficient to push thefluids into at least the near well bore area of a portion of thesubterranean formation (although typically below the pressure that willcreate or enhance fractures in the formation). Without limiting thedisclosure to any particular theory or mechanism, it is believed thatthe chemical additives of the present disclosure may change waterwetting characteristics of the rock surfaces within the subterraneanformation. In some embodiments, the chemical additives may also impart apositive charge to the rock surface, which may allow greater binding ofa positively charged scale inhibitor. When the chemical additives areapplied to a formation in a pre-flush treatment, it is believed thatthey may facilitate the adsorption of the scale inhibitor introduced ina subsequent treatment onto rock surfaces in the formation.

Among the many potential advantages to the methods and compositions ofthe present disclosure, only some of which are alluded to herein, themethods, compositions, and systems of the present disclosure may allowfor more effective application of scale inhibitor squeeze treatments ina number of ways. For example, in certain embodiments, the methods andsystems of the present disclosure may reduce the shut-in time needed toallow for effective adsorption and/or precipitation of the scaleinhibitor in the formation. In certain embodiments, the methods andsystems of the present disclosure may permit the scale inhibitor to morestrongly bond and/or adhere to rock surfaces within a formation and mayincrease the amount of time during which a scale inhibitor squeezetreatment may remain effective. The precipitation and/or adsorption ofthe scale inhibitor may at least partially depend on pH (e.g., generallytending to occur at higher pH conditions), and thus may be easilyreduced or removed from the formation by altering the pH conditionsdownhole (e.g., flushing a weak acid solution into the formation). Themethods and systems of the present disclosure may be able to place scaleinhibitor squeeze treatments without the use of concentrated brines,which sometimes cause formation damage. These and other benefits mayfacilitate the use of certain types of scale inhibitors that are moreenvironmentally-friendly but often impractical or unsuitable for use incertain types of formations.

In some embodiments, the chemical additives of the present disclosuremay include a choline chloride. In some embodiments, the cholinechlorides may be an organic compound having the formula[(CH₃)₃NCH₂CH₂OH]⁺ Cl⁻. For example, the chemical additives of thepresent disclosure may have the following chemical structure:

In certain embodiments, the chemical additive may be bifunctional. Forexample, in one or more embodiments, the chemical additive may includeboth a quaternary ammonium salt and an alcohol.

As discussed above, the present disclosure provides certain methods oftreating a subterranean formation with one or more scale inhibitors, forexample, in a scale inhibitor squeeze treatment. Scale inhibitor squeezetreatment technology may be employed in the industry when a scalecontrol treatment strategy is considered for prevention of scaledepositions in a reservoir and downhole tubing. Scale inhibitor squeezetechnology may offer a cost-effective method without requirements ofextra power once the scale inhibitor is placed in a reservoir. Incertain embodiments, the scale inhibitor squeeze treatment process mayinvolve several steps, as described in greater detail below. In someembodiments, the scale inhibitor squeeze treatment process may include apre-flush with a specially designed fluid. The injected pre-flush fluidcan push the formation brine away deeper into the formation to mitigateproblems resulting from any incompatibility between a forthcominginjected chemical and the formation brine. The cooling effect caused bythe pre-flush fluid injection can also reduce the rate of the scaleinhibitor adsorption and hence more scale inhibitor can be adsorbed onthe far distance of the reservoir rocks from well-bore. In certainembodiments, surfactants and squeeze enhancing additives, such as thechemical additives of the present disclosure, may be added in thepre-flush fluids to change the rock wettability in favor of theinhibitor adsorption to extend squeeze treatment life.

In certain embodiments, after the pre-flush stage, the scale inhibitorsqueeze treatment process may include adding a scale inhibitor mainpill. In some embodiments, the scale inhibitors of the main pill may bea phosphonic acid. In certain embodiments, the scale inhibitor may be aphosphonic acid selected from the group consisting of amino trimethylenephosphonic acid (ATMP), 1-hydroxyethane 1,1-diphosphonic acid (HEDP),amino tris(methylenephosphonic acid) (ATMP), ethylenediaminetetra(methylene phosphonic acid) (EDTMP), tetramethylenediaminetetra(methylene phosphonic acid) (TDTMP), hexamethylenediaminetetra(methylene phosphonic acid) (HDTMP), ethylene diamine tetra(methylene phosphonic acid) (EDTMPA), diethylenetriamine penta(methylenephosphonic acid) (DTPMP), bis(hexamethylene triamine penta (methylenephosphonic acid)) (BHMPTPMP), any derivative thereof, and anycombination thereof.

In some embodiments, the scale inhibitor squeeze treatment process mayinclude adding a scale inhibitor in a main pill in a concentration rangeof from about 5% to about 50%. In other embodiments, the scale inhibitorsqueeze treatment process may include adding a scale inhibitor in a mainpill in a concentration range of from about 5% to about 20%. Followingthe pre-flush, the inhibitor pill may be injected into a formation.During this injection stage, the pumping injection pressure may becarefully monitored. Sudden pressure spiking could be a sign ofincompatibility between the injected fluid and reservoir. In someembodiments, the treatment process may include a well shut-in step. Insome embodiments, after the main pill scale inhibitor injection, thewell may be shut in for a time period, for example, in the range of fromabout 6 hours to about 24 hours. In some embodiments, the scaleinhibitor squeeze treatment process may include a well production step.Following the shut-in period, wells may be placed back in normalproduction operations. Brine samples may be collected regularly foranalysis of the ions and residual scale inhibitors. Once the residualscale inhibitor concentration drops below the minimum inhibitorconcentration (MIC) required to control scale deposition, a new scaleinhibitor squeeze treatment may be needed. Without intending to belimited to any particular theory or mechanism, it is believed that thescale inhibitors may be precipitated with Ca²⁺, which may enable betterplacement within the formation while causing less formation damage.

In some embodiments, the chemical additives may be added in thepre-flush fluid. In some embodiments, the chemical additives of thepresent disclosure may be suitable for down-hole squeeze treatmentapplications with typical treatment rates ranged from 1% to 20% byvolume of the pre-flush fluid. In other embodiments, the chemicaladditives of the present disclosure may be suitable for down-holesqueeze treatment applications with typical treatment rates ranged from1% to 10% by volume of the pre-flush fluid. In still other embodiments,the chemical additives of the present disclosure may be suitable fordown-hole squeeze treatment applications with typical treatment ratesranged from 2% to 5% by volume of the pre-flush fluid. In certainembodiments, the chemical additives may be added to both the pre-flushfluids and the after-flush fluids. In some embodiments, the chemicaladditives may be added to the pre-flush fluids with typical treatmentrates ranged from 1% to 10% by volume of the pre-flush fluid and addedto the after-flush fluids with typical treatment rates ranged from 2% to3% by volume of the after-flush fluid.

In certain embodiments, the effectiveness of the scale inhibitor squeezetreatment and appropriate treatment rate may depend on the mineralogy ofthe rock within the subterranean formation. In some embodiments, theeffectiveness of the scale inhibitor squeeze treatment and optimaltreatment rate may depend on the applied scale inhibitor concentrationand/or volumes. In one or more embodiments, the effectiveness of thescale inhibitor squeeze treatment and optimal treatment rate may dependon downhole system conditions such as temperature and pH. For example,in some embodiments, the chemical additives of the present disclosuremay be used at temperatures in the range of from about 0° C. to about200° C. In other embodiments, the chemical additives of the presentdisclosure may be used at temperatures in the range of from about 50° C.to about 150° C. In still other embodiments, the chemical additives ofthe present disclosure may be used at temperatures in the range of fromabout 50° C. to about 100° C. In some embodiments, the chemicaladditives of the present disclosure may be used at a pH less than about8. In other embodiments, the chemical additives of the presentdisclosure may be used at a pH less than about 7. In still otherembodiments, the chemical additives of the present disclosure may beused at a pH less than about 5.

In some embodiments, a successful scale inhibitor squeeze treatment inaccordance with the present disclosure may provide goodretention/release properties to offer a long-term treatment life. Incertain embodiments, a successful scale inhibitor squeeze treatment inaccordance with the present disclosure may result in an MIC in a rangeof from about 1 ppm to about 30 ppm. In some embodiments, the scaleinhibitor may flow back to the surface at a concentration from severalthousand ppm (e.g., 10,0000 ppm) to about 1 ppm. Further, in someembodiments, a successful scale inhibitor squeeze treatment inaccordance with the present disclosure may result in zero orsubstantially zero formation damage when the scale inhibitor is placedin the reservoir.

An example of a scale inhibitor squeeze treatment process in accordancewith certain embodiments of the present disclosure is illustrated inFIGS. 1A and 1B. Referring now to FIG. 1A, a well site 100 is shown atwhich a well bore 120 has been drilled to penetrate a portion ofsubterranean formation 110. The well bore 120 may include an open hole,or it may include one or more casing strings (not shown) disposedtherein. A wellhead 105 is installed at the top of the well bore 120 towhich treating equipment 107 is coupled. The treating equipment 107 mayinclude pumps, fluid sources, blenders, liquid additive pumps, solidadditive hoppers, and/or other equipment used to prepare and/or injectfluids and additives into the well bore 120. For example, treatingequipment 107 may include a pump and blender system designed to mix thepre-flush fluids, treatment fluids, and/or after-flush fluids of thepresent disclosure. A string of production tubing 130 is disposed in thewell bore and extends from the well head down to approximately the depthof a hydrocarbon-bearing portion of the formation 110 and is held inplace by a packer 140. One or more perforations 150 in the well borewall or casing also provide fluid communication between thehydrocarbon-bearing portion of the formation 110 and the productiontubing 130.

In certain embodiments of the scale inhibitor squeeze treatments of thepresent disclosure, a pre-flush fluid 161 including one or more chemicaladditives is injected into the production tubing 130 using one or morepumps in the treating equipment 107. This pre-flush fluid also may beused to clean debris or other substances out of the producing area ofthe well bore 120 and formation 110 either by mechanically displacingthem from that region or by chemical treatment (e.g., acid dissolution).In certain embodiments, additional pre-flush fluids, cleaning fluids,etc. (not shown) may be injected into the well bore prior to pre-flushfluid 161. Next, a treatment fluid 163 of the present disclosureincluding a scale inhibitor is injected into the production tubing 130using one or more pumps in the treating equipment 107. In certainembodiments, the treatment fluid 163 also may be preceded by additionalfluids (not shown), such as spacer fluids used to separate treatmentfluid 163 from pre-flush fluid 161, or another pre-flush/treatment fluidthat includes a smaller concentration of the scale inhibitor (ascompared to treatment fluid 163) that may be used to prepare theformation to adsorb the scale inhibitor in treatment fluid 163.

Referring now to FIG. 1B, a later stage of the squeeze treatment fromFIG. 1A is shown at the same well site 100. Following the injection ofthe treatment fluid 163 (and, optionally, additional spacer fluids), anafter-flush/displacement fluid 165 is injected into the productiontubing 130 using one or more pumps in the treating equipment 107. Asshown, fluid 165 displaces the pre-flush fluid 161 and treatment fluid163 through the perforations 150 and into the near well bore area of theformation 110. This allows the chemical additives in fluid 161 toprepare the formation 110 for adsorption of the scale inhibitor thatthen enters the formation 110 in fluid 163.

Following the complete injection of fluid 165, the well bore 120 may beshut in for a period of time in order to allow the scale inhibitor tosoak in and adsorb onto the rock surfaces in formation 110. This periodof shut-in time may vary from a few hours to several days, depending ona number of factors that a person of skill in the art will recognizewith the benefit of this disclosure, such as the size and/or depth ofthe well bore, temperature and/or pressure conditions in the formation,the composition of the formation, the types and amounts of surfactantsand/or scale inhibitors used, and other similar factors.

Following that shut-in time, the well bore 120 may be brought intoproduction during which fluids from the formation 110 are permitted toflow out of the well bore 120 to the surface via production tubing 130.As that occurs, the produced fluids may carry some amount of theadsorbed scale inhibitor through the perforations 150 and productiontubing 130. In certain embodiments, this may prevent or reduce theformation of scales in those areas. In certain embodiments, additionaltools, tubulars, valves, and/or other equipment (not shown) may bedisposed along the production tubing 130. The flow of the produced fluidcarrying the scale inhibitor may prevent or reduce the formation ofscales in that equipment as well. In some instances, the concentrationof scale inhibitor in the fluids flowing out of the well bore may bemonitored during production to confirm that they are sufficient tocontrol scale formation at that well. If the concentration of the scaleinhibitor falls below a certain threshold amount, it may be determinedthat additional treatments (e.g., additional scale inhibitor squeezetreatments) will be performed.

The pre-flush fluids, treatment fluids, and/or after-flush fluids usedin the methods and systems of the present disclosure may include anybase fluid known in the art, including aqueous base fluids, non-aqueousbase fluids, and any combinations thereof. The term “base fluid” refersto the major component of the fluid (as opposed to components dissolvedand/or suspended therein), and does not indicate any particularcondition or property of that fluids such as its mass, amount, pH, etc.Aqueous fluids that may be suitable for use in the methods and systemsof the present disclosure may include water from any source. Suchaqueous fluids may include fresh water, salt water (e.g., watercontaining one or more salts dissolved therein), brine (e.g., saturatedsalt water), seawater, or any combination thereof. In most embodimentsof the present disclosure, the aqueous fluids include one or more ionicspecies, such as those formed by salts dissolved in water. For example,seawater and/or produced water may include a variety of divalentcationic species dissolved therein. In certain embodiments, the densityof the aqueous fluid can be adjusted, among other purposes, to provideadditional particulate transport and suspension in the compositions ofthe present disclosure. In certain embodiments, the pH of the aqueousfluid may be adjusted (e.g., by a buffer or other pH adjusting agent) toa specific level, which may depend on, among other factors, whether thatfluid is being used to enhance adsorption, desorption, precipitation, ordissolution of the scale inhibitor. One of ordinary skill in the art,with the benefit of this disclosure, will recognize when such densityand/or pH adjustments are appropriate. Examples of non-aqueous fluidsthat may be suitable for use in the methods and systems of the presentdisclosure include, but are not limited to, oils, hydrocarbons,alcohols, organic liquids/solvents, and the like. In certainembodiments, the fracturing fluids may include a mixture of one or morefluids and/or gases, including but not limited to emulsions, foams, andthe like.

In certain embodiments, the pre-flush fluids, treatment fluids, and/orafter-flush fluids used in the methods and systems of the presentdisclosure optionally may include any number of additional additives.Examples of such additional additives include, but are not limited to,salts, surfactants, acids, proppant particulates, diverting agents,fluid loss control additives, gas, nitrogen, carbon dioxide, surfacemodifying agents, tackifying agents, foamers, corrosion inhibitors,catalysts, clay control agents, biocides, friction reducers, antifoamagents, bridging agents, flocculants, H₂S scavengers, CO₂ scavengers,oxygen scavengers, lubricants, viscosifiers, breakers, weighting agents,relative permeability modifiers, resins, wetting agents, coatingenhancement agents, filter cake removal agents, antifreeze agents (e.g.,ethylene glycol), and the like. A person skilled in the art, with thebenefit of this disclosure, will recognize the types of additives thatmay be included in the fluids of the present disclosure for a particularapplication.

In certain embodiments, the fluids may be formed at a well site wherethe operation or treatment is conducted, either by batch mixing orcontinuous (“on-the-fly”) mixing. The term “on-the-fly” is used hereinto include methods of combining two or more components wherein a flowingstream of one element is continuously introduced into a flowing streamof at least one other component so that the streams are combined andmixed while continuing to flow as a single stream as part of theon-going treatment. Such mixing can also be described as “real-time”mixing. In other embodiments, the treatment fluids of the presentdisclosure may be prepared, either in whole or in part, at an offsitelocation and transported to the site where the treatment or operation isconducted. In introducing a treatment fluid of the present disclosureinto a portion of a subterranean formation, the components of thetreatment fluid may be mixed together at the surface and introduced intothe formation together, or one or more components may be introduced intothe formation at the surface separately from other components such thatthe components mix or intermingle in a portion of the formation to forma treatment fluid. In either such case, the treatment fluid is deemed tobe introduced into at least a portion of the subterranean formation forpurposes of the present disclosure.

Among the many potential advantages to the methods and compositions ofthe present disclosure, only some of which are alluded to herein, themethods, compositions, and systems of the present disclosure may provideimproved clay stabilization as a pre-flush agent for down-hole squeezetreatment. The methods and compositions of the present disclosure mayalso change the rock wettability towards more water wet for enhancedscale inhibitor retention in reservoirs and hence extend scale inhibitorsqueeze treatment life. The methods and compositions of the presentdisclosure may also be effective in a wide variety of oilfield waters.The methods and compositions of the present disclosure may also enhancea downhole squeeze treatment lifetime. The methods and compositions ofthe present disclosure may also provide a reduced squeeze treatmentfrequency and annualized deferred oil saving by applying the chemicaladditive as the squeeze treatment enhancer. The methods and compositionsof the present disclosure may also reduce the cost of spending on scalecontrol for an oil company.

To facilitate a better understanding of the present disclosure, thefollowing examples of certain aspects of certain embodiments are given.The following examples are not the only examples that could be givenaccording to the present disclosure and are not intended to limit thescope of the disclosure or claims.

Examples

The results from an initial field trial are presented in FIG. 2 . In thefield trial, two separate scale inhibitor squeeze treatments wereperformed. Before the first scale inhibitor squeeze treatment, nocholine chloride was added during the pre-flush stage. For the secondscale inhibitor squeeze treatment, a pre-flush fluid containing 2% byvolume of choline chloride was applied to the formation. The graph shownin FIG. 2 depicts the concentration of scale inhibitor in fluidsrecovered from the formation as a function of time. Line 201 representsthe scale inhibitor squeeze treatment after pre-flush treatment with thecholine chloride chemical additive of the present disclosure. Line 202represents the previous scale inhibitor squeeze treatment without thechemical additive of the present disclosure. The minimum scale inhibitorconcentration was found at 5 ppm. As seen from FIG. 2 , the treatmentlife (i.e., time to reach the minimum scale inhibitor concentration)increased more than 70 days when the choline chloride chemical additiveof the present disclosure is applied.

The results from an additional field trial are presented in FIG. 3 . Forthis field trial, a pre-flush fluid containing 3% by volume of cholinechloride was applied to the formation prior to performing the scaleinhibitor squeeze treatment. Line 301 represents the scale inhibitorsqueeze treatment with choline chloride chemical additive. The minimumscale inhibitor concentration was found at 5 ppm. As seen from FIG. 3 ,a treatment life (i.e., time to reach the minimum scale inhibitorconcentration) of over 450 days was achieved when the choline chloridechemical additive of the present disclosure is applied.

An embodiment of the present disclosure is a method includingintroducing a pre-flush fluid into at least a portion of a subterraneanformation, the pre-flush fluid including a chemical additive having thefollowing structural formula:

and introducing a treatment fluid including a scale inhibitor into theportion of the subterranean formation after at least a portion of thepre-flush fluid has been introduced into the portion of the subterraneanformation.

In one or more embodiments described in the preceding paragraph, themethod further includes allowing at least a portion of the scaleinhibitor to adsorb onto a rock surface in at least a portion of thesubterranean formation. In one or more embodiments described above, themethod further includes introducing an after-flush fluid into theportion of the subterranean formation after at least a portion of thescale inhibitor has been introduced into the portion of the subterraneanformation. In one or more embodiments described above, the methodfurther includes shutting in the well bore for a predetermined period oftime; and allowing one or more produced fluids in the subterraneanformation to flow from the formation and through the well bore after thepredetermined period of time has ended. In one or more embodimentsdescribed above, the scale inhibitor includes a phosphonic acid selectedfrom the group consisting of amino trimethylene phosphonic acid (ATMP),1-hydroxyethane 1,1-diphosphonic acid (HEDP), aminotris(methylenephosphonic acid) (ATMP), ethylenediamine tetra(methylenephosphonic acid) (EDTMP), tetramethylenediamine tetra(methylenephosphonic acid) (TDTMP), hexamethylenediamine tetra(methylenephosphonic acid) (HDTMP), ethylene diamine tetra (methylene phosphonicacid) (EDTMPA), diethylenetriamine penta(methylene phosphonic acid)(DTPMP), bis(hexamethylene triamine penta (methylene phosphonic acid))(BHMPTPMP), any derivative thereof, and any combination thereof. In oneor more embodiments described above, the method further includesallowing the chemical additive to increase a wettability of at least aportion of a rock surface in the portion of the subterranean formation.In one or more embodiments described above, the pre-flush fluid furtherincludes an amount of the scale inhibitor at a concentration smallerthan the amount of the scale inhibitor in the treatment fluid. In one ormore embodiments described above, the chemical additive is present inthe pre-flush fluid in an amount of from about 1% to about 10% by volumeof the fluid. In one or more embodiments described above, the scaleinhibitor is present in the treatment fluid in an amount of less thanabout 10% by volume of the fluid. In one or more embodiments describedabove, the pH in the portion of the subterranean formation is less thanabout 8.

Another embodiment of the present disclosure is a method includingintroducing a pre-flush fluid into at least a portion of a subterraneanformation, the pre-flush fluid including a chemical additive having thefollowing structural formula:

introducing a treatment fluid including a scale inhibitor into theportion of the subterranean formation after at least a portion of thepre-flush fluid has been introduced into the portion of the subterraneanformation; and introducing an after-flush fluid into the portion of thesubterranean formation after at least a portion of the scale inhibitorhas been introduced into the portion of the subterranean formation, theafter-flush fluid including the chemical additive.

In one or more embodiments described in the preceding paragraph, themethod further includes allowing at least a portion of the scaleinhibitor to adsorb onto a rock surface in at least a portion of thesubterranean formation. In one or more embodiments described above, themethod further includes shutting in the well bore for a predeterminedperiod of time; and allowing one or more produced fluids in thesubterranean formation to flow from the formation and through the wellbore after the predetermined of time has ended. In one or moreembodiments described above, the scale inhibitor includes a phosphonicacid selected from the group consisting of amino trimethylene phosphonicacid (ATMP), 1-hydroxyethane 1,1-diphosphonic acid (HEDP), aminotris(methylenephosphonic acid) (ATMP), ethylenediamine tetra(methylenephosphonic acid) (EDTMP), tetramethylenediamine tetra(methylenephosphonic acid) (TDTMP), hexamethylenediamine tetra(methylenephosphonic acid) (HDTMP), ethylene diamine tetra (methylene phosphonicacid) (EDTMPA), diethylenetriamine penta(methylene phosphonic acid)(DTPMP), bis(hexamethylene triamine penta (methylene phosphonic acid))(BHMPTPMP), any derivative thereof, and any combination thereof. In oneor more embodiments described above, the chemical additive is present inthe pre-flush fluid in an amount of from about 2% to about 3% by volumeof the fluid. In one or more embodiments described above, the chemicaladditive is present in the after-flush fluid in an amount of from about0.5%% to about 1.5% by volume of the fluid. In one or more embodimentsdescribed above, the pH in the portion of the subterranean formation isless than about 8.

Another embodiment of the present disclosure is a method includingintroducing a pre-flush fluid into at least a portion of a subterraneanformation, the pre-flush fluid including a chemical additive having thefollowing structural formula:

introducing a treatment fluid including a scale inhibitor into theportion of the subterranean formation after at least a portion of thepre-flush fluid has been introduced into the portion of the subterraneanformation; and introducing an after-flush fluid into the portion of thesubterranean formation after at least a portion of the scale inhibitorhas been introduced into the portion of the subterranean formation.

In one or more embodiments described in the preceding paragraph, themethod further includes allowing at least a portion of the scaleinhibitor to adsorb onto a rock surface in at least a portion of thesubterranean formation. In one or more embodiments described above, themethod further includes shutting in the well bore for a predeterminedperiod of time; and allowing one or more produced fluids in thesubterranean formation to flow from the formation and through the wellbore after the predetermined of time has ended.

Therefore, the present disclosure is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent disclosure may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. While numerous changes may be made bythose skilled in the art, such changes are encompassed within the spiritof the subject matter defined by the appended claims. Furthermore, nolimitations are intended to the details of construction or design hereinshown, other than as described in the claims below. It is thereforeevident that the particular illustrative embodiments disclosed above maybe altered or modified and all such variations are considered within thescope and spirit of the present disclosure. In particular, every rangeof values (e.g., “from about a to about b,” or, equivalently, “fromapproximately a to b,” or, equivalently, “from approximately a-b”)disclosed herein is to be understood as referring to the power set (theset of all subsets) of the respective range of values. The terms in theclaims have their plain, ordinary meaning unless otherwise explicitlyand clearly defined by the patentee.

What is claimed is:
 1. A method comprising: introducing a pre-flushfluid into at least a portion of a subterranean formation, the pre-flushfluid comprising a chemical additive having the following structuralformula:

wherein the chemical additive is present in an amount effective tochange the rock wettability towards more water wet for enhanced scaleinhibitor retention; and introducing a treatment fluid comprising ascale inhibitor into the portion of the subterranean formation after atleast a portion of the pre-flush fluid has been introduced into theportion of the subterranean formation.
 2. The method of claim 1 whereinthe chemical additive is present in an amount of 1% to 20% by volume ofthe pre-flush fluid.
 3. The method of claim 1 wherein the chemicaladditive is present in an amount of 1% to 10% by volume of the pre-flushfluid.
 4. The method of claim 1 wherein the chemical additive is presentin an amount of 2% to 5% by volume of the pre-flush fluid.
 5. The methodof claim 1 wherein a minimum inhibitor concentration is in a range offrom about 1 ppm to about 30 ppm.
 6. The method of claim 1 wherein thescale inhibitor comprises a phosphonic acid selected from the groupconsisting of amino trimethylene phosphonic acid (ATMP), 1-hydroxyethane1,1-diphosphonic acid (HEDP), amino tris(methylenephosphonic acid)(ATMP), ethylenediamine tetra(methylene phosphonic acid) (EDTMP),tetramethylenediamine tetra(methylene phosphonic acid) (TDTMP),hexamethylenediamine tetra(methylene phosphonic acid) (HDTMP), ethylenediamine tetra (methylene phosphonic acid) (EDTMPA), diethylenetriaminepenta(methylene phosphonic acid) (DTPMP), bis(hexamethylene triaminepenta (methylene phosphonic acid)) (BHMPTPMP), any derivative thereof,and any combination thereof.
 7. The method of claim 1 wherein thepre-flush fluid further comprises a scale inhibitor at a concentrationsmaller than the amount of the scale inhibitor in the treatment fluid.8. The method of claim 1 wherein the scale inhibitor is present in thetreatment fluid in an amount of about 5% to about 20% by volume of thefluid.
 9. The method of claim 1 wherein the pH in the portion of thesubterranean formation is less than about
 8. 10. A method for a squeezetreatment comprising: introducing a pre-flush fluid into at least aportion of a subterranean formation improving clay stabilization, thepre-flush fluid comprising a chemical additive having the followingstructural formula:

wherein the chemical additive is present in the pre-flush fluid in anamount of from about 1% to about 20% by volume of the pre-flush fluid,and wherein the chemical additive changes the rock wettability towardsmore water wet for enhanced scale inhibitor retention; introducing atreatment fluid comprising a scale inhibitor into the portion of thesubterranean formation after at least a portion of the pre-flush fluidhas been introduced into the portion of the subterranean formation; andintroducing an after-flush fluid into the portion of the subterraneanformation after at least a portion of the scale inhibitor has beenintroduced into the portion of the subterranean formation, theafter-flush fluid comprising the chemical additive.
 11. The method ofclaim 10 further comprising allowing at least a portion of the scaleinhibitor to adsorb onto a rock surface in at least a portion of thesubterranean formation while minimizing formation damage.
 12. The methodof claim 10 further comprising: shutting in the well bore for about 6 toabout 24 hours; and afterwards allowing one or more produced fluids inthe subterranean formation to flow from the formation and through thewell bore.
 13. The method of claim 10 wherein the scale inhibitorcomprises a phosphonic acid selected from the group consisting of: aminotrimethylene phosphonic acid (ATMP), 1-hydroxyethane 1,1-diphosphonicacid (HEDP), amino tris(methylenephosphonic acid) (ATMP),ethylenediamine tetra(methylene phosphonic acid) (EDTMP),tetramethylenediamine tetra(methylene phosphonic acid) (TDTMP),hexamethylenediamine tetra(methylene phosphonic acid) (HDTMP), ethylenediamine tetra (methylene phosphonic acid) (EDTMPA), diethylenetriaminepenta(methylene phosphonic acid) (DTPMP), bis(hexamethylene triaminepenta (methylene phosphonic acid)) (BHMPTPMP), any derivative thereof,and any combination thereof.
 14. The method of claim 10 wherein thechemical additive is present in an amount of 1% to 10% by volume of thepre-flush fluid.
 15. The method of claim 10 wherein the chemicaladditive is present in an amount of 2% to 5% by volume of the pre-flushfluid.
 16. The method of claim 10 wherein the chemical additive ispresent in the after-flush fluid in an amount of from about 0.5% toabout 1.5% by volume of the fluid.
 17. The method of claim 10 whereinthe pH in the portion of the subterranean formation is less than about8.
 18. A method comprising: introducing a pre-flush fluid into at leasta portion of a subterranean formation, the pre-flush fluid comprising achemical additive having the following structural formula:

wherein the chemical additive is present in the pre-flush fluid in anamount of from about 1% to about 20% by volume of the fluid effective tochange the rock wettability towards more water wet for enhanced scaleinhibitor retention; and introducing a treatment fluid comprising ascale inhibitor into the portion of the subterranean formation after atleast a portion of the pre-flush fluid has been introduced into theportion of the subterranean formation; and introducing an after-flushfluid into the portion of the subterranean formation after at least aportion of the scale inhibitor has been introduced into the portion ofthe subterranean formation.
 19. The method of claim 18 furthercomprising allowing at least a portion of the scale inhibitor to adsorbonto a rock surface in at least a portion of the subterranean formation.20. The method of claim 18 further comprising: shutting in the well borefor about 6 hours to about 24 hours; and allowing one or more producedfluids in the subterranean formation to flow from the formation andthrough the well bore after the predetermined period of time has ended.